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Search: id:A056256
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| A056256 |
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Indices of primes in sequence defined by A(0) = 33, A(n) = 10*A(n-1) + 53 for n > 0. |
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+0
1
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| 1, 11, 29, 59, 115, 289, 631, 1063, 1493, 5431, 7361
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Numbers n such that (350*10^n - 53)/9 is prime.
Numbers n such that digit 3 followed by n >= 0 occurrences of digit 8 followed by digit 3 is prime.
Numbers corresponding to terms <= 631 are certified primes. For number corresponding to 1063 and 1493 see P. De Geest, PDP Reference Table.
a(n) = A082709(n-1) - 2.
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REFERENCES
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Klaus Brockhaus and Walter Oberschelp, Zahlenfolgen mit homogenem Ziffernkern, MNU 59/8 (2006), pp. 462-467.
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LINKS
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P. De Geest, PDP Reference Table
Makoto Kamada, Factorizations of 388...883.
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EXAMPLE
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383 is prime, hence 1 is a term.
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PROGRAM
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(PARI) a=33; for(n=0, 1500, if(isprime(a), print1(n, ", ")); a=10*a+53)
(PARI) for(n=0, 1500, if(isprime((350*10^n-53)/9), print1(n, ", ")))
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CROSSREFS
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Cf. A000533, A002275, A082709.
Sequence in context: A138248 A021005 A054692 this_sequence A043139 A043919 A120946
Adjacent sequences: A056253 A056254 A056255 this_sequence A056257 A056258 A056259
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KEYWORD
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nonn,hard,more
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AUTHOR
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Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 18 2000
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EXTENSIONS
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Additional comments from Klaus Brockhaus (klaus-brockhaus(AT)t-online.de) and Walter Oberschelp (oberschelp(AT)informatik.rwth-aachen.de), Dec 20 2004
Edited by njas, Jun 15 2007
More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 02 2008
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